EP0024254B1 - Aminotriazine polycarboxylic acids and their partial esters, their preparation and their use as hardening agents for epoxy resins - Google Patents

Description

From the U.S. No. 2 337 220, the reaction of mercaptans, in particular aliphatic mercaptocarboxylic acids, with N-memethylol or N-halomethyl derivatives of amides is known. The reaction between thioglycolic acid and an N-methylolamide is said to lead to the formation of an N- (carboxymethylthiomethyl) amide, i.e. there is an etherification and not an esterification. The particular disclosures are limited to the use of N-hydroxymethylamides of aliphatic monocarboxylic acids having at least 12 carbon atoms, but amides of numerous other types of acids and also urea, thiourea and meiamin and their substitution products are mentioned as possible reactants.

The U.S. U.S. Patent No. 2,763,649 describes the formation of curable, ternary condensation products by reacting (a) a formaldehyde condensation product of a compound of the aminotriazine or urea group or an ether thereof with a low molecular weight alcohol, (b) a carbon chain with at least 7 carbon atoms and a aliphatic compound containing a reactive hydrogen atom bonded to a hetero atom and (c) a hydroxy or mercaptocarboxylic acid or hydroxy or mercaptosulfonic acid. If (a) is a methylolated aminotriazine or its ether, 1 mole (c) is used per mole (a).

The preparation of aminotriazine polycarboxylic acids is not disclosed in any of these references.

It has now been found that the reaction of an aminotriazine containing at least two N-methylol or N-alkoxymethyl groups with at least two equivalents of a mercaptocarboxylic acid gives aminotriazine polycarboxylic acids in which the carboxyl groups are bonded to the aminotriazine ring via thioether bridges. If one also starts from a poly (alkoxymethylamino) triazine, a subsequent esterification can take place to a certain extent, so that the product can contain not only the aminotriazine polycarboxylic acid but also its partial ester, the esterifying group being the same as the original one ethereal group; With methoxymethylaminotriazines, methyl esters of polycarboxylic acids can also form. It has also been found that partial esters can be obtained by replacing a portion of the mercaptocarboxylic acid with its ester or by partially reacting the aminotriazine polycarboxylic acid with an alcohol.

Polycarboxylic acids are well known as hardeners for epoxy resins, i.e. Substances that contain more than one 1,2-epoxy group per average molecule. Such known acids often require high temperature and / or prolonged heating to cure the resin. It was also found that the new polycarboxylic acids and their partial esters containing at least two carboxyl groups cure epoxy resins when heated to moderate temperatures for only a short time.

worin R' für eine Gruppe der Formel -NR²R³, eine geradkettige oder verzweigte Alkylgruppe mit 1 bis 17 Kohlenstoffatomen, eine einkernige Arylgruppe mit 6 bis 10 Kohlenstoffatomen, eine Phenylalkylengruppe mit 1 bis 4 Kohlenstoffatomen im Alkylenteil oder eine Gruppe der Formel

steht, R² und R³ gleich oder verschieden sein können und je ein Wasserstoffatom, eine Gruppe der Formel -CHR⁴OR⁵, eine Gruppe der Formel -CHR^4-S-R^6-COOQ oder eine Gruppe der Formel

darstellen, wobei R² und R3 in den Formeln I und III so ausgewählt sind, dass höchstens eine davon eine Gruppe der Formel III und mindestens zwei davon eine Gruppe der Formel -CHR⁴-S-R⁶-COOQ bedeuten, m eine ganze Zahl von 1 bis '3 ist, R⁴ jeweils für ein Wasserstoffatom oder eine geradkettige oder verzweigte Alkylgruppe mit 1 bis 3 Kohlenstoffatomen, R⁵ jeweils für ein Wasserstoffatom oder eine geradkettige oder verzweigte Alkylgruppe mit 1 bis 8 und vorzugsweise 1 bis 4 Kohlenstoffatomen und R⁶ jeweils für eine gegebenenfalls durch eine weitere Gruppe -COOQ substituierte, zweiwertige geradkettige oder verzweigte Alkylengruppe mit 1 bis 4 Kohlenstoffatomen stehen, Q jeweils ein Wasserstoffatom oder eine geradkettige oder verzweigte Alkylgruppe mit 1 bis 8 Kohlenstoffatomen darstellt, derart, dass im Durchschnitt jeweils mindestens zwei Q in der Formel I für ein Wasserstoffatom stehen, und n null oder 1 ist.The present invention accordingly relates to aminotriazine polycarboxylic acids and their partial esters with at least two free carboxyl groups, of the general formula

wherein R 'is a group of the formula -NR ² R ³ , a straight-chain or branched alkyl group having 1 to 17 carbon atoms, a mononuclear aryl group having 6 to 10 carbon atoms, a phenylalkylene group having 1 to 4 carbon atoms in the alkylene part or a group of the formula

stands, R ² and R ^{3 may be the} same or different and each a hydrogen atom, a group of the formula -CHR ⁴ OR ⁵ , a group of the formula -CHR ^4- SR ^6- COOQ or a group of the formula

represent, wherein R ² and R3 in the formulas I and III are selected such that at most one of them is a group of the formula III and at least two of them are a group of the formula -CHR ⁴ -SR ⁶ -COOQ, m is an integer of 1 to '3, R ⁴ each represents a hydrogen atom or a straight-chain or branched alkyl group having 1 to 3 carbon atoms, R ⁵ each represents a hydrogen atom or a straight-chain or branched alkyl group having 1 to 8 and preferably 1 to 4 carbon atoms and R ⁶ each represent a divalent straight-chain or branched alkylene group with 1 to 4 carbon atoms optionally substituted by a further group -COOQ, Q each represents a hydrogen atom or a straight-chain or branched alkyl group with 1 to 8 carbon atoms, such that on average at least two Q in formula I each represent a hydrogen atom and n is zero or 1.

As indicated above, one (but not more than one) of the various symbols R ² and R ³ in formula I can represent a triazine ring of formula 111. A symbol R ² or R ³ in this ring can represent yet another ring of the formula III, and in this way a chain of substituted triazine rings linked by alkylene or alkylene ether bridges can be formed. In order to facilitate the preparation of the new compounds and to achieve the best results in the curing of epoxy resins, the acids and esters of the formula I preferably have a molecular weight of at most 2000.

The group R ^I is preferably a group -NR ² R ³ , where R ² and R ^{3 have} the meaning given above, but it can also be, for example, a heptadecyl, nonyl, propyl or benzyl group and in particular a methyl, phenyl or be an undecyl group.

All symbols R ⁴ preferably each represent a hydrogen atom. At least one Q and at least one R ⁵ preferably represent an alkyl group, such as a methyl, n-butyl, isobutyl or 2-ethylhexyl group. All groups R ⁶ in the formula I are preferably a methylene, ethylene or 2-carboxyethylidene group.

worin zwei bis sechs von den R⁷ je für eine Gruppe der Formel -CH₂SCH₂COOQ, -CH₂SCH₂-CH₂COOQ, -CH2SCH(COOQ)CH2COOQ oder -CHiSCH(CH₃)COOQ, wobei Q die oben angegebene Bedeutung hat und gegebenenfalls verbleibende R⁷ je ein Wasserstoffatom bedeuten, entsprechen, sowie solche, die im wesentlichen auch der Formel

worin zwei bis vier von den R⁸ je für eine Gruppe der Formel -CH₂SCH₂COOQ, -CH₂SCH₂COOQ, -CH₂SCH(COOQ)CH2COOQ oder -CH2SCH(CH3)-COOQ stehen, wobei Q die oben angegebene Bedeutung hat und gegebenenfalls verbleibende R⁸ je ein Wasserstoffatom bedeuten, und R⁹ eine Methyl-, Phenyl- oder Undecylgruppe darstellt, entsprechen.Other preferred substances of the formula I are the acids and esters, which are also essentially of the formula

wherein two to six of the R ⁷ each for a group of the formula -CH ₂ SCH ₂ COOQ, -CH ₂ SCH ₂ -CH ₂ COOQ, -CH2SCH (COOQ) CH2COOQ or -CHiSCH (CH ₃ ) COOQ, where Q is the above has the meaning indicated and any remaining R ^7's each represent a hydrogen atom, and those which essentially also have the formula

wherein two to four of the R ⁸ each represent a group of the formula -CH ₂ SCH ₂ COOQ, -CH ₂ SCH ₂ COOQ, -CH ₂ SCH (COOQ) CH2COOQ or -CH2SCH (CH3) -COOQ, where Q is the above has the meaning indicated and any remaining R ⁸ each represent a hydrogen atom and R ^{9 represents} a methyl, phenyl or undecyl group.

Specific examples of _'acids of formula I are hexakis (N-2-carboxyäthylthiomethyl) melamine, hexakis (N-carboxymethylthiomethyl) melamine, tetrakis (N-2-carboxymethylthiomethyl) -acetoguanamin, tetrakis (N-2- carboxyethylthiomethyl) - benzoguanamine and tetrakis (N-2-carboxyethylthiomethyl) lauroguanamine.

mit einem Moläquivalent eines gegebenenfalls alkylierten Kondensationsprodukts aus einem Aminotriazin und einem Aldehyd, der allgemeinen Formel

worin R⁶ die oben angegebene Bedeutung hat, R¹⁰ eine Gruppe -NR¹¹R¹² oder eine geradkettige oder verzweigte Alkylgruppe mit 1 bis 17 Kohlenstoffatomen, eine einkernige Arylgruppe mit 6 bis 10 Kohlenstoffatomen, eine Phenylalkylengruppe mit 1 bis 4 Kohlenstoffatomen im Alkylenteil oder eine Gruppe der Formel

darstellt, R" und R¹² gleich oder verschieden sein können und je ein Wasserstoffatom, eine Gruppe -CH⁴-O-R⁵ oder eine Gruppe der Formel

bedeuten, wobei R⁴, R⁵, m und n die oben angegebene Bedeutung haben und R" und R¹² in der Verbindung der Formel VII so ausgewählt sind, dass höchstens eines davon eine Gruppe der Formel IX und mindestens zwei davon eine Gruppe der Formel -CHR⁴-OR⁵ bedeuten, herstellen.The acids and partial esters of the formula I can be obtained by reacting at least 2 molar equivalents of a mercaptocarboxylic acid of the general formula

with a molar equivalent of an optionally alkylated condensation product of an aminotriazine and an aldehyde, of the general formula

wherein R ^{6 has} the meaning given above, R ^{10 is} a group -NR ¹¹ R ¹² or a straight-chain or branched alkyl group having 1 to 17 carbon atoms, a mononuclear aryl group having 6 to 10 carbon atoms, a phenylalkylene group having 1 to 4 carbon atoms in the alkylene part or one Group of the formula

represents, R "and R ^{12 may be the} same or different and each a hydrogen atom, a group -CH ⁴ -OR ⁵ or a group of the formula

mean, wherein R ⁴ , R ⁵ , m and n have the meaning given above and R "and R ¹² in the compound of formula VII are selected such that at most one of them is a group of formula IX and at least two of them are a group of formula -CHR ⁴ -OR ⁵ mean, produce.

This reaction can be carried out in such a way that the components are at room temperature or preferably at an elevated temperature, usually between 50 ° and 150 ° C., either without a solvent or in the presence of a suitable solvent such as water, methanol, ethanal, dioxane, acetone, glacial acetic acid, benzene or toluene and, if desired, mixed in the presence of an acidic catalyst such as sulfuric acid or hydrochloric acid.

If at least one of the groups R "and R" in the formula VII represents a group of the formula -CHR ⁴ -OR ⁵ , where R ^{5 represents} an alkyl group as indicated above, the product is usually a mixture of the acid of the formula I, in which Q represents a hydrogen atom and a minor amount of the ester of the formula I, in which Q represents a similar alkyl group R ⁵ , preferably a methyl, n-butyl, isobutyl or 2-ethylhexyl group. If desired, such mixtures can be separated using conventional methods, but they can usually be used without such separation as hardeners for epoxy resins. The use of the partial esters is often advantageous, for example if the hardened epoxy resin is to be more flexible than would be obtained using only an unesterified polycarboxylic acid according to the invention as the hardener.

worin R⁶ die oben angegebene Bedeutung hat und Q' eine geradkettige oder verzweigte Alkylgruppe mit 1 bis 8 Kohlenstoffatomen, z.B. eine Methyl-, n-Butyl-, Isobutyl- oder 2-Äthylhexylgruppe bedeutet, als einer der Reaktionspartner mitverwendet, um einen Teilester der Formel zu erhalten.After a modification of the above method according to the invention, an ester of the formula

wherein R ^{6 has} the meaning given above and Q 'is a straight-chain or branched alkyl group having 1 to 8 carbon atoms, for example a methyl, n-butyl, isobutyl or 2-ethylhexyl group, is also used as one of the reactants to form a partial ester of Get formula.

This modification can be substituted for the use of an alkylated aminotriazine / aldehyde condensation product (ie a compound of the formula V in which at least one of the groups R "and R ^{12 is} a group of the formula -CHR ^4- -0-R ⁵ , where R ^{5 is} an alkyl group as stated above), or also when using such an alkylated condensation product, in order to increase the content of ester groups (which may be the same or different from the ester groups formed by reaction with the liberated alcohol).

worin Q' die oben angegebene Bedeutung hat, verestert.In a further production method for the partial esters according to the invention, the aminotriazine polycarboxylic acids of the formula I, in which at least three Q's each represent a hydrogen atom, are prepared in a conventional manner using an alcohol of the formula

wherein Q 'has the meaning given above, esterified.

The proportion of an ester of formula X or an alcohol of formula XI should of course not be so high that the product contains on average fewer than two free carboxyl groups per molecule, since the product would otherwise be unusable as a hardener for epoxy resins.

und mindestens zwei Moläquivalente eines Aldehyds der Formel

worin R¹³ eine unsubstituierte Aminogruppe, eine geradkettige oder verzweigte Alkylgruppe mit 1 bis 17 Kohlenstoffatomen, eine einkernige Arylgruppe mit 6 bis 10 Kohlenstoffatomen, eine Phenylalkylengruppe mit 1 bis 4 Kohlenstoffatomen im Alkylenteil oder eine Gruppe der Formel

darstellt sowie m und R⁴ die oben angegebene Bedeutung haben, umsetzt.Another production method for acids and partial esters of the formula I is that at least two molar equivalents of a mercaptocarboxylic acid of the formula VI and, if appropriate, a corresponding amount of an ester of the formula X with one molar equivalent of an aminotriazine of the formula

and at least two molar equivalents of an aldehyde of the formula

wherein R ^{13 is} an unsubstituted amino group, a straight-chain or branched alkyl group having 1 to 17 carbon atoms, a mononuclear aryl group having 6 to 10 carbon atoms, a phenylalkylene group having 1 to 4 carbon atoms in the alkylene part or a group of the formula

represents and m and R ^{4 have} the meaning given above, implemented.

This reaction is preferably carried out under aqueous conditions, using the acid of the formula IV, optionally the ester of the formula X and the aminotriazine of the formula XII, if appropriate with heating, until they dissolve as a result of salt formation, and then the aldehyde of the formula XIII is added. The mixture is then stirred until the reaction is practically complete. The reaction can take place at room temperature, but the reactants are preferably heated to a temperature of 50 ° to 100 ° C.

In a variant of the above method using the same molar proportions, the acid of the formula VI (and optionally the ester of the formula X) can first be mixed with the aldehyde of the formula XIII under aqueous or anhydrous conditions and then the aminotriazine of the formula XII can be added. This reaction can also take place at room temperature or at elevated temperature, and the reactants are preferably heated to a temperature of 50 ° to 100 ° C.

A particularly preferred embodiment of this invention consists in reacting melamine in the absence of an ester of the formula X with 2 to 6 molar equivalents of thioglycolic acid, 2-mercaptapropionic acid, 3-mercaptopropionic acid or mercaptosuccinic acid and with 2 to 6 molar equivalents of formaldehyde, the same number of equivalents of the Formaldehyde and mercapto acid can be applied. In a further particularly preferred embodiment, acetoguanamine, benzoguanamine or lauroguanamine is reacted in the absence of an ester of the 'formula X with 2 to 4 molar equivalents of thioglycolic acid, 2-mercaptopropionic acid,' 3-mercaptopropionic acid or mercaptosuccinic acid, the same number of equivalents of the formaldehyde and the mercapto acid be applied.

mit mindestens zwei Moläquivalenten einer Mercaptocarbonsäure der obigen Formel VI herstellen, wobei R" eine Gruppe der Formel -NR¹⁵R¹⁶, eine geradkettige oder verzweigte Alkylgruppe mit 1 bis 17 Kohlenstoffatomen, eine einkernige Arylgruppe mit 6 bis 10 Kohlenstoffatomen, eine Phenylalkylengruppe mit 1 bis 4 Kohlenstoffatomen im Alkylenteil oder eine Gruppe der 'Formel

bedeutet, worin m die oben angegebene Bedeutung hat, R¹⁵ und R¹⁶ gleich oder verschieden sein können und je für ein Wasserstoffatom oder eine Gruppe der Formel -CH₂NR¹⁷R¹⁸ stehen, worin entweder R¹⁷ ein Wasserstoffatom oder eine geradkettige oder verzweigte Alkylgruppe mit 1 bis 4 Kohlenstoffatomen und R¹⁸ eine solche (gleiche oder verschiedene) Alkylgruppe darstellen oder R" und R¹⁸ zusammen mit dem Stickstoffatom, an das sie gebunden sind, einen einwertigen, einkernigen heterocyclischen Rest mit bis zu 8 Kohlenstoffatomen bedeuten, wobei R¹⁵ und R¹⁶ so ausgewählt werden, dass die Verbindung der Formel XV mindestens zwei Gruppen der Formel -CH₂NR¹⁷R¹⁸ aufweist, und wobei die Umsetzung dadurch erfolgt, dass man die Reaktionspartner miteinander entweder allein oder in einem Lösungsmittel wie Xylol, Methanol, Äthanol, Dioxan, Aceton, Eisessig, Benzol, Toluol oder Pyridin unter Abspaltung des Amins der Formel

erhitzt.Aminotriazine polycarboxylic acids of the formula I, in which all R ⁴ and Q each represent a hydrogen atom, can also be obtained by reacting a molar equivalent of an aminotriazine of the general formula

with at least two molar equivalents of a mercaptocarboxylic acid of the formula VI above, where R "is a group of the formula -NR ¹⁵ R ¹⁶ , a straight-chain or branched alkyl group having 1 to 17 carbon atoms, a mononuclear aryl group having 6 to 10 carbon atoms, a phenylalkylene group having 1 to 4 carbon atoms in the alkylene part or a group of the 'formula

means in which m has the meaning given above, R ¹⁵ and R ^{16 may be the} same or different and each represents a hydrogen atom or a group of the formula -CH ₂ NR ¹⁷ R ¹⁸ , in which either R ^{17 is} a hydrogen atom or a straight-chain or branched Alkyl groups with 1 to 4 carbon atoms and R ^{18 represent} such an (identical or different) alkyl group or R "and R ¹⁸ together with the nitrogen atom to which they are attached represent a monovalent, mononuclear heterocyclic radical having up to 8 carbon atoms, where R ¹⁵ and R ¹⁶ are selected so that the compound of the formula XV has at least two groups of the formula -CH ₂ NR ¹⁷ R ¹⁸ , and the reaction is carried out by reacting the reactants with one another either alone or in a solvent such as xylene or methanol , Ethanol, dioxane, acetone, glacial acetic acid, benzene, toluene or pyridine with elimination of the amine of the formula

heated.

The reactants are usually heated to a temperature in the range from 100 ° to 200 ° C.

The aminotriazines of the formula XV used as starting materials can be prepared by a Mannich reaction between an aminotriazine of the formula XII, formaldehyde and a primary or secondary amine of the formula XVII or a salt of such an amine. 'The type of amine used is generally not critical, but for reasons of economy and to avoid undesired by-products and to facilitate cleavage during the reaction with the mercaptocarboxylic acid, it is preferred that R "for a hydrogen atom and R ¹⁸ for a methyl or ethyl group or both R ¹⁷ and R ^{18 represent} a methyl or ethyl group or R ¹⁷ and R ¹⁸ together form a group of the formula - (CH ₂ ) ₅ - or a group of the formula - (CH ₂ ) ₂ O- (CH ₂ ) ₂ - represent.

As indicated above, the fiction acids and partial esters useful as hardeners for epoxy resins.

Accordingly, the present invention further relates to curable compositions which comprise an epoxy resin and an aminotriazine polycarboxylic acid or a partial ester of the formula I, and a process for curing an epoxy resin which consists in preparing and heating such a composition.

An effective, i.e. curing amount of polycarboxylic acid or ester used. The ratio between the acid or the partial ester and the epoxy resin depends on the particular acid or ester used and on the properties desired for the curable composition and the cured product. The optimal ratio can easily be determined by methods familiar to the person skilled in the art. As an explanation, however, it should be mentioned that normally so much polycarboxylic acid or partial ester is used that there are 0.8 to 1.2 carboxyl groups per epoxy group in the epoxy resin.

enthalten, worin entweder R" und R²¹ je ein Wasserstoffatom darstellen, in welchem Fall R²⁰ ein Wasserstoffatom oder eine Methylgruppe bedeutet, oder R" und R²¹ zusammen =CH₂CH₂- darstellen, in welchem Fall R²⁰ ein Wasserstoffatom bedeutet.Epoxy resins which can be used in these compositions are preferably those which have groups of the formula which are bonded directly to oxygen, nitrogen or sulfur atoms

contain, in which either R "and R ²¹ each represent a hydrogen atom, in which case R ^{20 represents} a hydrogen atom or a methyl group, or R" and R ²¹ together represent = CH ₂ CH ₂ -, in which case R ^{20 represents} a hydrogen atom.

Examples of such resins are polyglycidyl and poly (β-methylglycidyl) esters which can be obtained by reacting a compound containing two or more carboxylic acid groups per molecule with epichlorohydrin, glycerol dichlorohydrin or β-methylepichlorohydrin in the presence of alkali. Such polyglycidyl esters can be derived from aliphatic polycarboxylic acids, e.g. Oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid or dimerized or trimerized linoleic acid; cycloaliphatic polycarboxylic acids such as tetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, hexahydrophthalic acid and 4-methylhexahydrophthalic acid; and derived from aromatic polycarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid.

Further examples are polyglycidyl and poly (β-methylglycidyl) ether, which are reacted by reacting a compound containing at least two free alcoholic and / or phenolic hydroxyl groups per molecule with the corresponding epichlorohydrin under alkaline conditions or in the presence of an acidic catalyst subsequent alkali treatment are available. These ethers can be mixed with poly (epichlorohydrin) from acyclic alcohols such as ethylene glycol, diethylene glycol and higher poly (oxyethylene) glycols, propane-1,2-diol and poly (oxypropylene) glycols, propane-1,3 -dio), butane-1,4-diol, poly- (oxytetramethylene) glycols, pentane-1,5-diol, hexane-1,6-diol, hexane-2,4,6-triol, glycerol, 1, 1,1-trimethylolpropane, pentaerythritol and sorbitol; from cycloaliphatic alcohols such as resorcite, quinite, bis (4-hydroxycyclohexyl) methane, 2,2-bis (4-hydroxycyclohexyl) propane and 1,1-bis (hydroxymethyl) cyclohexene-3; and from alcohols with aromatic nuclei such as N, N-bis - (2-hydroxyethyl) aniline and p, p'-bis (2-hydroxyethylamino) diphenylmethane. You can also from mononuclear phenols such as resorcinol u. Hydroquinone and the like polynuclear phenols such as bis (4-hydroxyphenyl) methane, 4,4'-dihydroxydiphenyl, bis (4-hydroxyphenyl) sulfone, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, 2, 2-bis - (4-hydroxyphenyl) propane (otherwise known as bisphenol A) and 2,2-bis (3; 5-dibromo-4-hydroxyphenyl) propane and from aldehydes such as formaldehyde, acetaldehyde, chloral and furfural Novolaks formed with phenols such as phenol itself and phenol ring-substituted by chlorine atoms or alkyl groups each having up to nine carbon atoms, such as 4-chlorophenol, 2-methylphenol and 4-tert-butylphenol.

Poly (N-glycidyl) compounds include, for example, those obtained by dehydrochlorination of the reaction products of epichlorohydrin with amines containing at least two amino hydrogen atoms, such as aniline, n-butylamine, bis (4-aminophenyl) methane and bis (4-methylaminophenyl) ) -methane can be obtained; Triglycidyl isocyanurate; as well as N, N'-diglycidyl derivatives of cyclic alkylene ureas such as ethylene urea and 1,3-propylene urea, and hydantoins such as 5,5-dimethylhydantoin.

Poly (S-glycidyl) compounds are, for example, the di-S-glycidyl derivatives of dithiols such as ethane-1,2-dithiol and bis (4-mercaptomethylphenyl) ether.

Examples of epoxy resins with groups of the formula XVIII, in which R "and R ²¹ together represent a -CH2CH2 group, are bis- (2,3-epoxy-cyclopentyl) ether, 2,3-epoxycyclopentyl-glycidyl ether and 1,2- Bis- (2,3-epoxycyclopentyloxy) ethane.

Epoxy resins in which the 1,2-epoxy groups are bonded to heteroatoms of various types are also suitable, for example the N, N, O-triglycidyl derivative of 4-aminophenol, the glycidyl ether / glycidyl ester of salicylic acid, N-glycidyl-N '- ( 2-glycidyloxypropyl) -5,5-dimethylhydantoin and 2-glycidyloxy-1,3-bis- (5,5-dimethyl-1-glycidylhydantoinyl-3) propane.

It is also possible to use epoxy resins in which some or all of the epoxy groups are middle-class, such as vinylcyclohexene dioxide, limonene dioxide, dicyclopentadiene dioxide, 4-oxatetracyclo [6.2.1.0 ^2.7 .0 ^3.5 ] undecyl- (9) -glycidyl ether, 1, 2-bis- (4-oxatetracyclo [6.2.1.0 ^2.7 .0 ^3.5 ] -undecyl- - (9) -oxy) -ethane, the 3,4-epoxycyclohexylmethyl ester of 3 ', 4'-epoxycyclohexanecarboxylic acid and its'6,6'-dimethyl derivative, the bis- (3,4-epoxycyclohexanecarboxylic acid ester) of ethylene glycol, adipic acid - bis- (3,4-epoxy-6-methylcyclohexyl ester), 3- (3,4-epoxycyclohexyl) -8,9-epoxy-2,4-dioxaspiro [5.5] undecane and epoxidized butadiene or copolymers of Butadiene with ethylene compounds such as styrene and acrylonitrile.

If desired, epoxy resin mixtures can be used.

Preferred epoxy resins are the polyglycidyl ethers, polyglycidyl esters and N, N '= diglycidyl hydantoins, in particular those which have a 1,2 - epoxy content of more than 0.5 equivalent per kilogram. Particularly preferred resins are N, N'-diglycidyl-5,5-dimethylhydantoin and the polyglycidyl ethers of 2,2-bis (4-hydroxyphenyl) propane, bis- (4-hydroxyphenyl) methane or from formaldehyde and phenol or novolaks formed by a chlorine atom or an alkyl hydrocarbon group having from one to nine carbon atoms ring-substituted phenol.

The new compositions can also contain suitable accelerators such as tertiary amines and quaternary ammonium salts, in particular imidazole, dimethylaminoethanol, pyridine and tetrabutylammonium iodide, or metal octanoates, in particular zinc octanoate or stannous octanoate. Furthermore, plasticizers such as dibutyl phthalate and dioctyl phthalate, inert diluents such as tars and bitumen and so-called reactive diluents, in particular monoepoxides such as n-butyl glycidyl ether, isooctyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, acrylate methacrylate, and glycidyl acrylate, the glycidyl acrylate, the glycidyl acrylate, the glycidyl acrylate, the glycidyl acrylate, the glycidyl acrylate, the glycidyl acrylate, the glycidyl acrylate, the glycidyl acrylate, the glycidyl acrylate, the glycidyl acrylate, the glycidyl acrylate, the glycidyl acrylate, the compositions are present. They can also contain additives such as fillers, reinforcing agents, colorants, leveling agents, flame retardants and mold release oils. Examples of suitable extenders, fillers and reinforcing agents are glass fibers, carbon fibers, glass beads, mica, quartz powder, calcium carbonate, cellulose, kaolin, wollastonite, colloidal silica with a large specific surface area, powdered polyvinyl chloride and powdered polyolefin hydrocarbons such as polyethylene and polypropylene.

The curable compositions according to the invention are used as laminating resins, sintering powders, impregnating and casting resins, molding compounds, putties and sealing compounds, embedding and insulating compounds for the electrical industry and as adhesives and in the production of such products, and they are particularly suitable for use as coatings , both as paints and varnishes and as powder coatings.

The following examples illustrate the invention. Parts are parts by weight unless otherwise stated.

An epoxy resin is a diglycidyl ether of bisphenol A, which is pre-extended with bisphenol A to an epoxide content of 1.3 val / kg.

Epoxy resin II is a diglycidyl ether of bisphenol A which has an epoxy content of 5.23 eq / kg.

Epoxy resin III is a diglycidyl ether of bisphenol A which has an epoxy content of 5.1 eq / kg.

Epoxy resin IV is N, N'-diglycidyl-5,5-dimethylhydantoin.

Epoxy resin V is a diglycidyl ether similar to epoxy resin I, which is however pre-extended to an epoxy content of 1.0 val / kg.

example 1

3-Mercaptopropionic acid (99% pure, 322 g; 3 mol) is weighed into a 1 liter glass flask equipped with a stirrer, thermometer and reflux condenser. The flask is heated until the contents reach 95 ° C. and then melamine (63 g; 0.5 mol) is added. A temperature of 90 ° C. is set at which the contents are liquid but still contain some undissolved melamine. Over the course of 4 minutes, an aqueous 36.5% by weight formaldehyde solution (246 g; 3 mol) stabilized with 6% methanol is added. The mixture clears and an exothermic reaction begins. The temperature is kept at 100 ° C. and the mixture is then cooled to a white paste.

The paste is mixed with the same weight of water and the same weight of ethanol. The mixture is heated to 56 ° C., which gives a clear solution. When cooling, crystals separate from this solution. After standing overnight, the crystals are filtered off and recrystallized from 50% aqueous ethanol. The crystals are dried at 70 ° C in a vacuum oven to give Hexaki _'s- (N-2 - carboxyäthylthiomethyl) melamine is obtained of melting point 153-154 ° C.

The elementary analysis shows the following results:

The found acid number of this material is 7.38 val / kg compared to a theoretical value of 7; 19 val / kg.

Example 2

Example 1 is repeated, but at the end of the reaction volatile material is removed by distillation, first at atmospheric pressure and then in vacuo, the mixture being finally heated to 140 ° C./64 torr. The product is cooled to 110 ° C. and poured into one flat bowl and allows the clear colorless viscous liquid to cool. The product, crude hexakis (N-2-carboxyethylthiomethyl) melamine (421 g; 100 ° / o yield) is stored for 11 days at 25 ° -35 ° C and converts to a hard, white, translucent mass, which can be ground into powder. The powder has an acid number of 7.34 val / kg (theoretical value 7.19 val / kg) and melts at 134-138 ° C. A sample is recrystallized from 50% aqueous ethanol and then melts at 148-152 ° C.

Example 3

Liquid, methylated melamine / formaldehyde resin (287.5 g; non-volatile content 97%; melamine: formaldehyde: methyl molar ratio = 1: 6: 4.5) are added at 100 ° C. to thioglycolic acid (332.2 g; 98, 9% pure). The addition takes 30 minutes, keeping the temperature at 90-110 ° C. The mixture is then heated to 120 ° C. to distill off volatiles and the distillation is completed at 128 ° C. in a water pump vacuum. The distillate weighs 109 g and consists of methanol from the reaction between thioglycolic acid and the methylated resin, volatile material from the methylated resin itself and water, methanol and dimethoxymethane from the condensation of two or more melamine rings with one another.

The still hot distillation residue is poured onto a flat tray and allowed to cool. This material is a clear, hard, colorless, resinous solid that softens at 62 ° C. Gel permeation chromatography confirms that the molecular weight has increased significantly as a result of the reaction; While the starting material is predominantly composed of mononuclear types, the product largely has a molecular weight of almost 2000, which is shown by exceeding the exclusion limit of the column and thus providing further evidence that two or more melamine rings have been linked.

The acid number of this material is 4.73 val / kg; the value calculated on the amount of thioglycolic acid used is 7.0 val / kg. It can be assumed that the low acid number is a result of a partial further reaction of the carboxyl groups in the etherified product with the released methanol to the corresponding methyl esters. This assumption is demonstrated by saponification of the product with normal sodium hydroxide solution. whereby the neutralization number increases sharply. There are no signs of esterification of the released methanol with unreacted thioglycolic acid.

Further evidence confirming the formation of the esters can be found when examining the ¹³ C-NMR spectrum, where two new peaks appear, none of which in the spectra of the melamine resin starting material, the thioglycolic acid or the product from Example 7 (see below ) is available:

The shifts in the new peaks attributable to the presence of methyl ester are underlined.

Example 4

"Cymel" 11,56 (74.1 g, 0.14 mol; a highly n-butylated hexamethylol melamine supplied by American Cyanamid Corporation with a Gardner-Holdt viscosity of Z ₂ -Z ₄ at 25 ° C, a nitrogen content of 16.7% and a solids content of 98%; "Cymel" is a trademark) and 3-mercaptopropionic acid (45.9 g, 0.42 mol) are heated in an Erlenmeyer flask on a hotplate equipped with a magnetic stirrer. The mixture is heated to 70 ° C for 40 minutes and then to 110 ° C for 5 minutes. The thiol number of the product is less than 0.01 mol / kg, which corresponds to over 99.7% conversion of the original thiol group content. The acid number of this product is 3.21 val / kg; the calculated value for tris (N-2-carboxyethylthiomethyl) tris (N-butoxymethyl) melamine dissolved in the released reaction n-butanol is 3.60 eq / kg. _' The low acid number found is caused by partial esterification.

Example 5

The procedure is again as in Example 4, using 78.1 g (0.1'5 mol) of "Cymel" 11'56 and 41.9 g (0.44 mol) of freshly distilled thioglycolic acid. The thiol number of the product is over 99% conversion and the product has an acid number of 3.01 eq / kg; the calculated value for tris (N-carboxymethylthiomethyl) tris (N-n-butoxymethyl) melamine dissolved in the released reaction n-butanol is 3.80 eq / kg. The low acid number found is caused by partial esterification.

Example 6

Cymel 11,56 (76.0 g, 0.145 mol) and thio malic acid (44.0 g, 0.29 mol) are heated to 75-85 ° C. with stirring for 40 minutes, after which time the thiol number has increased to over 99% sales. Xylene (23.4 g) is added to give a clear, viscous, slightly light brown solution. The acid number of the product is 3.68 eq / kg (expressed as the value before dilution with xylene); the calculated value for im released Reaction n-butanol dissolved bis- (N-1,2- (dicarboxy) -ethylthiomethyl) tetrakis (Nn-butoxymethyl) melamine is 4.09 eq / kg. The low acid number found is caused by partial esterification.

Example 7

Thioglycolic acid (282 g; 97.9% pure; 3 mol) is mixed with melamine (64 g; 0.5 mol) and water (200 ml) to form a uniform viscous slurry. Formaldehyde solution (36.3% in water, 24'6 g; 3 mol) is added and the mixture is heated to 65 ° C., the mixture clarifying. The mixture is then heated under reflux for 30 minutes and distilled at atmospheric pressure. After collecting 323 g of distillate and after the flask has reached 110 ° C, the distillation is interrupted and the residue is cooled, giving 441 g of a clear viscous liquid. Lstündiges by heating 1 g at 120 ° C one finds a content of 87.0% _{nonvolatiles'} in this product. Its acid number, based on the non-volatile content, is 7.68 val / kg. The calculated value for hexakis (N-carboxymethylthiomethyl) melamine is 7.99 val / kg.

Example 8

Melamine (32 g; 0.25 mol), 3-mercaptopropionic acid (98.5% pure; 80.7 g; 0.75 mol) and distilled water (1'50 ml) are heated together and stirred. A clear solution of the melamine salt of 3-mercaptopropionic acid forms at 93 ° C. 36.6% aqueous formaldehyde solution (61.5 g; 0.75 mol) is slowly added at 100 ° C. The addition takes 7 minutes, and because of the exothermic nature of the reaction, the temperature remains at 85-90 ° C without external heat. The solution becomes cloudy and, after stirring for a further 6 minutes, no odor of formaldehyde is detectable. Then the stirrer is switched off and the mixture is allowed to cool. The upper layer is then poured off from a whitish, sticky lower layer, which is further cooled, crushed, filtered off and washed with ice-cold water. The solid is dried in a vacuum drying cabinet at 40 ° C., 114 g (93.7% of theory) of symmetrical and / or asymmetrical tris (N-2-carboxyethylthiomethyl) melamine as a white powder with a melting point of 1.66 ° up to 175 ° C and an acid number of 6.01 val / kg (theoretical value 6.24 val / kg). The product has no detectable thiol content.

Example 9

Acetoguanamine (6.25 g; 0.05 mol) and 3-mercaptopropionic acid (21.23 g; 0.20 mol) are stirred together and heated. When 85 ° C is reached, the mixture clarifies, and at 95 ° C, 36.0% aqueous formaldehyde (1,667 g; 0.20 mol) is added and then distilled water (20 ml). The mixture is heated to 100 ° C. and a white precipitate is formed. After heating for a further 20 minutes at 100 ° C., the mixture is cooled to room temperature, filtered and the precipitate is washed in cold water. After drying in a vacuum drying cabinet, the yield is 18.7 g (62.6% of theory); the product melts at 220-227 ° C. Its acid number is 6.64 val / kg, while the theoretical value for tetrakis - (N-2-carboxyethylthiomethyl) acetoguanamine is 6.69 val / kg.

Example 10

Benzoguanamine (9.35 g; 0.05 mol) and 3-mercaptopropionic acid (21.23 g; 0.20 mol) are stirred together and heated. The mixture clarifies at 96 ° C., and 36.0% strength aqueous formaldehyde (16.67 g; 0.20 mol) is added. The temperature is kept at 82-89 ° C. for 20 minutes and then cooling is applied. An oil separates, which solidifies with further stirring. Distilled water (100 ml) is added and the white solid is filtered off and dried in a vacuum drying cabinet. The yield of crude material is 28.8 g g (87.3% of theory); this melts at 110-118 ° C. The acid number of the material is 6.30 val / kg, while the theoretical value for tetrakis (N-2-carboxyethylthiomethyl) benzoguanamine is 6.06 val / kg.

Example 11

“Cymel” 1156 (38.8 g), 2-ethylhexylthioglycolate (40.8 g) and 3-mercaptopropionic acid (21.2 g) are mixed in a flask. The molar ratio of these components is 1: 2.63: 2; 63. The flask is connected to a rotary evaporator and heated for 9½ hours in a water bath at 95 ° C. A vacuum is applied and 16.9_g of distillate collect in the course of 2 hours. The product remaining in the flask (82; 6 g) has a thio number of 0.22 val / kg, which indicates over 95% conversion.

It is a colorless, easily pourable, slightly cloudy liquid with an acid number of 2.35 val / kg. The calculated acid number for a tris (N-2-carboxyethylthiomethyl) tris-N - 2- (ethyl) hexyloxycarbonylmethylthiomethyl) melamine is 2.66 eq / kg.

Example 12

Benzoguanamine (9.35 g; 0.05 mol), 3-mercaptopropionic acid (21.23 g; 0.20 mol) and n-butyraldehyde (14.42 g; 0.20 mol) are heated to 64 ° C. with stirring at what temperature the reaction becomes exothermic. After 30 minutes at 50-60 ° C the mixture is a clear liquid with traces of a suspended solid. The mixture is cooled to room temperature, which gives a viscous pulpy mass.

ersetzt worden sind.The product is suspended in cold acetone (50 ml) and filtered. The residue is washed twice with 25 ml of cold acetone and dried, which gives 13.7 g of white powder with a melting point of 142-148 ° C. This product has an acid number of 4.1 val / kg, which indicates that on average 3.4 hydrogen atoms bound to nitrogen in the benzoguanamine molecule by groups of the formula

have been replaced.

Example 13

Melamine (31.6 g; 0.25 mol), 3-mercaptopropionic acid (79.6 g; 0.75 mol) and distilled water (1'50 g) are heated; when the mixture reaches 83 ° C, a clear liquid is formed. This is then cooled to 75 ° C. and slowly mixed with n-butyraldehyde (54.0 g; 0.75 mol), the temperature being kept between 70 and 80 ° C.

When the addition is complete, the mixture is heated under reflux for 4½ hours.

The mixture is cooled and the clear aqueous layer is removed. The organic layer is washed with distilled water (2X250 ml) and then dissolved in 10% sodium carbonate solution (500 ml). The solution is neutralized with acetic acid solution (10%), whereby the product precipitates. This is filtered off and dried, which gives 106.5 g of symmetrical and / or asymmetrical tris (N-1- (2-carboxyethylthio) butyl) melamine as a white solid with an acid number of 4.40 eq / kg. The calculated acid number for tris (N-1- (2-carboxyethylthio) butyl) melamine is 4.54 eq / kg. The ¹³ C-NMR spectrum of the product is consistent with such a compound.

Example 14

Lauroguanamine (53.1 g, 0.2 mol), 3-mercaptopropionic acid (84.9 g, 0.8 mol) and 50 g of water are heated to 85 ° C., the mixture forming two liquid phases. 65.8 g (0.8 mol) of 36.5% strength aqueous formaldehyde solution are then added dropwise. After adding about 1 _' 5 g, the reaction mixture becomes a clear yellow solution. The addition of the formaldehyde is completed in the course of four minutes, the temperature of the reaction mixture rising to 93 ° C. The mixture is then heated under reflux (98 ° -100 ° C.) for 30 minutes, during which time a white solid precipitates. After cooling, the mixture is filtered and the white solid is washed several times with hot water. The product yield is 109 g after drying in vacuo. The product, essentially tetrakis (N-2-carboxyethylthiomethyl) lauroguanamine, has an acid number of 4.38 val / kg and a negligibly small thiol number and melts at 155 ° C (determined on the Kofler bench).

Example 15

The recrystallized hexakis (N-2-carboxyethylthimethyl) melamine (8.34 g, 0.01 mol) and 2.95 g (0.025 mol) of 2-n-butoxyethanol prepared according to Example 2 are heated to 150 ° C . Initially, a thick, white, barely stirrable paste forms, but after 40 minutes it turns into a thin, clear, colorless solution. The mixture is heated at 1'50 ° C for a further 100 minutes and then cooled. The product, a clear, colorless liquid with a sweet smell, has an acid number of 3.48 val / kg (5.49 val / kg calculated for the initial mixture; the calculated value for a product that averages' 2; 5 2- (n-Butoxyethoxycarbonyl) - ethylthiomethyl groups per molecule is 3.80 eq / kg) and a solids content (determined by heating a sample of 0.5 g at 120 ° C. for 60 minutes) of 92.4% (calculated initial value 73 , 9%).

Example 16

• 'EEA bezeichnet 2-Äthoxyäthylacetat
• ^b als Verlaufmittel zugesetzt.

A composition with the following content is prepared:

• 'EEA denotes 2-ethoxyethyl acetate
• ^b added as a leveling agent.

An additional amount of 2-ethoxyethyl acetate is added to reduce the viscosity of the mixture to about 80 mPas.

Steel plates are sprayed with this solution and baked at 200 ° C for 15 minutes.

The following observations and tests are carried out on the coatings:

These results show that the coatings are cross-linked and have very good mechanical properties.

Example 17

Portions of the products from Examples 4, 5 and 6 are each mixed separately with the stoichiometric amount of epoxy resin II and diluted with 2-n-butoxyethanol. The formulations are given in the table below:

• ^dDer Widerstand gegen AMK wird bestimmt, indem man den Überzug 20mal mit einem in Äthylmethylketon getränkten Wattebausch hin hin und her reibt.
• ' Die Härte wird beurteilt, indem man den Film mit dem Fingernagel anzukratzen versucht.

Approximately 100 micron thick films of these compositions are poured onto glass plates, dried at room temperature for 1 hour and then baked for ½ hour as indicated below. The results are shown in the table below:

• ^d Resistance to AMK is determined by rubbing the coating back and forth 20 times with a cotton ball soaked in ethyl methyl ketone.
• 'The hardness is assessed by trying to scratch the film with your fingernail.

Example 18

Mix the product from Example 7 (5.0 g) with epoxy resin III (6.8 g) and dilute with 2-ethoxyethanol (5 ml) to give a clear solution. A film of this solution is poured onto a glass plate and baked for 30 minutes at 100 ° C., which results in a tough, hard film which, when rubbed 10 times, remains unaffected by a cotton ball soaked in acetone.

Example 19

Samples of 1.0 g weight of the products from Examples 8, 9 and 10 are dissolved in dimethylaminoethanol (DMAE) and water or in dimethylformamide (DMF) and mixed with the epoxy resin IV or epoxy resin II described above. The mixtures are poured onto glass plates to a thickness of 100 μ and baked in the oven at 1,50 ° C. for 30 minutes. Then they are subjected to rubbing 20 times with a cotton ball soaked in ethyl methyl ketone. The results are as shown in the following table:

Example 20

The product from Example 11 (1 g) is mixed with 4.3 g of a 60% strength solution of the epoxy resin V in 2-n-butoxyethanol and diluted with 2-ethoxyethanol (1 g).

A film of 75 µ wet thickness is poured onto a glass plate and then heated to 150 ° C for 30 minutes. After that, the film turns out to be clear and tough. When rubbed 20 times with cotton soaked in xylene, it remains unaffected and suffers only a slight softening if it is rubbed 20 times with cotton soaked in 2-ethoxyethanol.

Example 21

The partial ester (1 g) prepared in Example 15 is mixed with 5.87 g of a 60% solution of the epoxy resin V in 2-n-butoxyethanol and spread in a 75 µ thick layer on a glass plate. The layer is cured at 150 ° C. for 30 minutes, a clear, colorless, glossy, tough, flexible film being formed which, when rubbed 20 times, remains unaffected by a cotton ball soaked in 2-n-butoxyethanol.

In a further experiment, a mixture of 5.24 g of the product from Example 15 and 3.48 g of epoxy resin II is heated to the lower temperature of 100 ° C. for 30 minutes. A film with similar properties is created.

Claims (10)

1. An aminotriazinepolycarboxylic aoid or a partial ester thereof containing at least two free carboxyl groups, characterised by the general formula

wherein

R^I represents a group of formula -NR²R³, a straight chain or branched alkyl group of 1 to 17 carbon atoms, a mononuclear aryl group of 6 to 10 carbon atoms, a phenylalkylene group containing 1 to 4 carbon atoms in the alkylene moiety, or represents a group of formula

R² and R³ may be the same or different and each represents a hydrogen atom, a group of formula -CHR⁴OR⁵, a group of formula

or a group of formula

R² and R³ in formulae I and III being selected such that at most one of them represents a group of formula III and at least two of them each represent a group of the formula -CHR⁴-S-R⁶--COOQ, m represents an integer from 1 to 3, each R⁴ represents a hydrogen atom or a straight chain or branched alkyl group of 1 to 3 carbon atoms, each R⁵ represents a hydrogen atom or a straight chain or branched alkyl group of 1 to 8 carbon atoms, each R⁶ represents a divalent straight chain or branched alkylene group of 1 to 4 carbon atoms which is unsubstituted or substituted by a further group of the formula -COOQ, each Q represents a hydrogen atom or a straight chain or branched alkyl group of 1 to 8 carbon atoms, such that on average at least two symbols Q in formula I each represent hydrogen, and n is zero or 1.

2. An acid or ester according to claim 1, having a molecular weight of at most 2000.

3. An acid or ester according to either of claims 1 or 2, wherein each R⁴ represents a hydrogen atom.

4. An acid or ester according to one of the preceding claims, wherein each R' represents a methylene, ethylene, ethylidene, or 2-carboxy- ethylidene group.

'5. An acid or ester according to claim 4, which also corresponds substantially to the formula

wherein from two to six of R⁷ each denote a group of formula -CH₂SCH₂COOQ, -CH₂SCH2-CH₂COOQ, -CH₂SCH(COOQ)CH₂COOQ, or -CH₂-SCH(CH₃)COOQ, where Q is as defined in claim 1, and any remaining R⁷ each represent a hydrogen atom.

6. An acid or ester according to claim 4, which also corresponds substantially to the formula

wherein from two to four of R⁸ each denote a group of formula -CH₂SCH₂COOQ, -CH2SCH2CH₂-COOQ, -CH₂SCH(COOQ)CH₂COOQ, or -CH2SCH-(CH₃)COOQ, wherein Q is as defined in claim 1, and any remaining R⁸ each represent a hydrogen atom, and R⁹ represents a methyl, phenyl, or undecyl group.

7. A process for the preparation of an aminotriazinepolycarboxylic acid or a partial ester thereof according to any one of the preceding claims, which process comprises reacting at least 2 molar equivalents of a mercaptocarboxylic acid of the general formula

and optionally a desired amount of an ester of the formula

with one molar equivalent of an optionally alkylated condensation product of an aminotriazine and an aldehyde, of the general formula

wherein R⁶ is as defined in claim 1 or claim 4, Q' is a straight chain or branched alkyl group of 1 to 8 carbon atoms, R'° is a group of the formula -NR¹¹R¹² or a straight chain or branched alkyl group of 1 to 17 carbon atoms, a mononuclear aryl group of 6 to 10 carbon atoms, a phenylalkylene group containing 1 to 4 carbon atoms in the alkylene moiety, or a group of the formula

R" and R¹² may be the same or different and each is a'hydrogen atom, a group of the formula -CHR⁴-O-R⁵ or a group of the formula

and R⁴ is as defined in claim 1 or claim 3 and R⁵, m and n are as defined in claim 1, and R" and R¹² in the compound of formula VII are chosen such that at most one is a group of the formula IX and at least two are a group of the formula -CHR⁴-OR⁵.

8. A process for the preparation of an aminotriazinepolycarboxylic acid or a partial ester thereof according to any one of claims 1 to 6, which process comprises reacting at least two molar equivalents of a mercaptocarboxylic acid of the formula

and optionally a desired amount of an ester of the formula

with one molar equivalent of an aminotriazine of the formula

and at least two molar equivalents of an aldehyde of the formula

wherein R⁶ is as defined in either claim 1 or claim 4 and Q¹ is as defined in claim 7, R¹³ is an unsubstituted amino group, a straight chain or branched alkyl group of 1 to 17 carbon atoms, a mononuclear aryl group of 6 to 10 carbon atoms, a phenylalkylene group containing 1 to 4 carbon atoms in the alkylene moiety, or a group of the formula

m is as defined in claim 1 and R⁴ is as defined in claim 1 or claim 3.

9. A process for the preparation of a partial ester according to any one of claims 1 to 6, which process comprises partially esterifying an aminotriazinepolycarboxylic acid aeeording to any one of claims 1 to 6, wherein at least three of the symbols Q are each a hydrogen atom, with an alcohol of the formula Q¹OH, wherein Q' is as defined in claim 7.

10. Utilisation of an aminotriazinepolyoarbox- ylic acid or a partial ester thereof according to any one of claims 1 to 6 as hardener for epoxy resins.